cl-structures: Tree cleanup

cl-structures/src/tree.rs

@@ -158,6 +158,9 @@ impl<T> Node<T> {
         std::mem::replace(&mut self.value, value)
     }
 
+    pub fn parent(&self) -> Option<Ref<T>> {
+        self.parent
+    }
     pub fn children(&self) -> &[Ref<T>] {
         &self.children
     }

cl-structures/src/tree/tree_ref.rs

@@ -10,7 +10,7 @@ use std::{marker::PhantomData, num::NonZeroUsize};
 pub struct Ref<T: ?Sized>(NonZeroUsize, PhantomData<T>);
 
 impl<T: ?Sized> Ref<T> {
-    /// Constructs a new [TreeRef] with the given index
+    /// Constructs a new [Ref] with the given index
     pub fn new_unchecked(index: usize) -> Self {
         // Safety: index cannot be zero because we use saturating addition on unsigned type.
         Self(